Background: This study explores effective fixation methods for Pauwel type III femoral neck fractures by evaluating the biomechanical benefits of adding a screw to the Femoral Neck System (FNS). Methods: Computed tomography (CT) scans of an 82-year-old female patient with an intertrochanteric fracture were used to establish a finite element femur model with heterogeneous material properties. Finite element models of Pauwel type III fractures were created with and without an additional screw. The central and inferior trajectories of the FNS bolt were examined separately and combined with an additional screw for virtual fixation. Walking and stair-climbing loads were applied. Results: With the addition of a screw, both peak maximum and minimum principal strains consistently stayed comparable or decreased in models with both central and inferior bolt trajectories, while the volume of elements with principal strain exceeding 1% decreased by more than half. The peak von Mises stress observed in the implants ranged from 215.7 to 359.3 MPa, remaining below the titanium alloy's yield strength of 800 MPa. For normal walking, the addition of a screw to the central bolt trajectory model decreased the fracture gap by 50.6% and reduced sliding distance by 8.6%. For the inferior bolt trajectory, the gap was reduced by 57.9% and sliding distance by 25.0%.Under stair-climbing conditions, these improvements were also evident; the central trajectory model saw a halved fracture gap and a 7.9% decrease in sliding distance, while the inferior trajectory model experienced a 55.7% gap reduction and a 27.2% decrease in sliding distance. The additional screw increased the area ratio of the fracture site experiencing interfragmentary compression 34%–39%, while the additional screw alleviated peak interfragmentary compression by 12%–18% under both normal walking and stair-climbing conditions. Conclusions The addition of a screw reduced the fracture gap, sliding distance, and peak interfragmentary compression, while increasing the area ratio of interfragmentary compression under both walking and stair-climbing loads, regardless of the FNS bolt trajectory, suggesting a better mechanical environment for fracture healing.

Background: This study explores effective fixation methods for Pauwel type III femoral neck fractures by evaluating the biomechanical benefits of adding a screw to the Femoral Neck System (FNS). Methods: Computed tomography (CT) scans of an 82-year-old female patient with an intertrochanteric fracture were used to establish a finite element femur model with heterogeneous material properties. Finite element models of Pauwel type III fractures were created with and without an additional screw. The central and inferior trajectories of the FNS bolt were examined separately and combined with an additional screw for virtual fixation. Walking and stair-climbing loads were applied. Results: With the addition of a screw, both peak maximum and minimum principal strains consistently stayed comparable or decreased in models with both central and inferior bolt trajectories, while the volume of elements with principal strain exceeding 1% decreased by more than half. The peak von Mises stress observed in the implants ranged from 215.7 to 359.3 MPa, remaining below the titanium alloy's yield strength of 800 MPa. For normal walking, the addition of a screw to the central bolt trajectory model decreased the fracture gap by 50.6% and reduced sliding distance by 8.6%. For the inferior bolt trajectory, the gap was reduced by 57.9% and sliding distance by 25.0%.Under stair-climbing conditions, these improvements were also evident; the central trajectory model saw a halved fracture gap and a 7.9% decrease in sliding distance, while the inferior trajectory model experienced a 55.7% gap reduction and a 27.2% decrease in sliding distance. The additional screw increased the area ratio of the fracture site experiencing interfragmentary compression 34%–39%, while the additional screw alleviated peak interfragmentary compression by 12%–18% under both normal walking and stair-climbing conditions. Conclusions The addition of a screw reduced the fracture gap, sliding distance, and peak interfragmentary compression, while increasing the area ratio of interfragmentary compression under both walking and stair-climbing loads, regardless of the FNS bolt trajectory, suggesting a better mechanical environment for fracture healing.

Background: This study explores effective fixation methods for Pauwel type III femoral neck fractures by evaluating the biomechanical benefits of adding a screw to the Femoral Neck System (FNS). Methods: Computed tomography (CT) scans of an 82-year-old female patient with an intertrochanteric fracture were used to establish a finite element femur model with heterogeneous material properties. Finite element models of Pauwel type III fractures were created with and without an additional screw. The central and inferior trajectories of the FNS bolt were examined separately and combined with an additional screw for virtual fixation. Walking and stair-climbing loads were applied. Results: With the addition of a screw, both peak maximum and minimum principal strains consistently stayed comparable or decreased in models with both central and inferior bolt trajectories, while the volume of elements with principal strain exceeding 1% decreased by more than half. The peak von Mises stress observed in the implants ranged from 215.7 to 359.3 MPa, remaining below the titanium alloy's yield strength of 800 MPa. For normal walking, the addition of a screw to the central bolt trajectory model decreased the fracture gap by 50.6% and reduced sliding distance by 8.6%. For the inferior bolt trajectory, the gap was reduced by 57.9% and sliding distance by 25.0%.Under stair-climbing conditions, these improvements were also evident; the central trajectory model saw a halved fracture gap and a 7.9% decrease in sliding distance, while the inferior trajectory model experienced a 55.7% gap reduction and a 27.2% decrease in sliding distance. The additional screw increased the area ratio of the fracture site experiencing interfragmentary compression 34%–39%, while the additional screw alleviated peak interfragmentary compression by 12%–18% under both normal walking and stair-climbing conditions. Conclusions The addition of a screw reduced the fracture gap, sliding distance, and peak interfragmentary compression, while increasing the area ratio of interfragmentary compression under both walking and stair-climbing loads, regardless of the FNS bolt trajectory, suggesting a better mechanical environment for fracture healing.

Background: This study explores effective fixation methods for Pauwel type III femoral neck fractures by evaluating the biomechanical benefits of adding a screw to the Femoral Neck System (FNS). Methods: Computed tomography (CT) scans of an 82-year-old female patient with an intertrochanteric fracture were used to establish a finite element femur model with heterogeneous material properties. Finite element models of Pauwel type III fractures were created with and without an additional screw. The central and inferior trajectories of the FNS bolt were examined separately and combined with an additional screw for virtual fixation. Walking and stair-climbing loads were applied. Results: With the addition of a screw, both peak maximum and minimum principal strains consistently stayed comparable or decreased in models with both central and inferior bolt trajectories, while the volume of elements with principal strain exceeding 1% decreased by more than half. The peak von Mises stress observed in the implants ranged from 215.7 to 359.3 MPa, remaining below the titanium alloy's yield strength of 800 MPa. For normal walking, the addition of a screw to the central bolt trajectory model decreased the fracture gap by 50.6% and reduced sliding distance by 8.6%. For the inferior bolt trajectory, the gap was reduced by 57.9% and sliding distance by 25.0%.Under stair-climbing conditions, these improvements were also evident; the central trajectory model saw a halved fracture gap and a 7.9% decrease in sliding distance, while the inferior trajectory model experienced a 55.7% gap reduction and a 27.2% decrease in sliding distance. The additional screw increased the area ratio of the fracture site experiencing interfragmentary compression 34%–39%, while the additional screw alleviated peak interfragmentary compression by 12%–18% under both normal walking and stair-climbing conditions. Conclusions The addition of a screw reduced the fracture gap, sliding distance, and peak interfragmentary compression, while increasing the area ratio of interfragmentary compression under both walking and stair-climbing loads, regardless of the FNS bolt trajectory, suggesting a better mechanical environment for fracture healing.

Purpose: This study aims to analyze the learning curve of hand-assisted laparoscopic living donor nephrectomy (HLDN) conducted by a trained gastrointestinal surgeon. Methods: A retrospective analysis was performed on the perioperative clinical data of 96 consecutive patients who underwent HLDN from May 2013 to March 2023. The learning curve was evaluated using the cumulative sum (CUSUM) test based on operation time and risk-adjusted CUSUM for postoperative complications. Patients were divided into three groups (novice, development, and competency phases) based on changes in operation time. Patient demographics and perioperative outcomes were compared between each group. Results: Among the patients, 35 were male, with a mean age of 48.9 ± 11.3 years and a mean body mass index (BMI) of 24.5 ± 3.2 kg/m 2 . The novice phase (phase 1) included the first 30 cases, with the development phase (phase 2) up to the 65th case. Operation times were significantly different across phases, averaging 263.2 ± 33.4, 211.1 ± 34.4, and 161.1 ± 31.3 minutes for phases 1, 2, and 3, respectively (P < 0.001). Blood loss decreased gradually across phases (phase 1, 264.7 ± 144.4 mL; phase 2, 239.7 ± 166.3 mL; phase 3, 198.8 ± 103.5 mL), though not statistically significant. BMI impacted operation time only in phase 1. Overall postoperative complications occurred in 13 cases (Clavien-Dindo grade I, 4 cases;grade II, 9 cases), with no significant differences across phases. Conclusion HLDN can be safely performed by a trained gastrointestinal surgeon, with approximately 30 cases needed to achieve proficiency.

Purpose: Despite the increasing use of immediate breast reconstruction (IBR), its oncologic safety in the setting of neoadjuvant chemotherapy (NACT) needs to be comprehensively clarified in breast cancer management. The objective of the present study was to analyze the oncologic safety of IBR following NACT. Methods: In total, 587 patients with breast cancer who underwent a total mastectomy (TM) with IBR after NACT between 2008 and 2017 at a single institution were retrospectively reviewed. The reviewed patients with IBR following skin-sparing mastectomy (SSM) or nipple-sparing mastectomy (NSM) were matched 1:3 to patients who underwent TM alone after NACT. Matching variables included age, clinical T and N stages before NACT, response to NACT, pathologic T and N stages, and molecular subtypes. Results: After propensity score matching, 95 patients who underwent IBR following SSM/ NSM after NACT (IBR group) and 228 patients who underwent TM alone after NACT (TM group) were selected. The median follow-up period was 73 (range, 5–181) months after matching. After matching, there were no significant differences between the two groups in 5-year locoregional recurrence-free survival (88.8% vs. 91.2%, p = 0.516), disease-free survival (67.3% vs. 76.6%, p = 0.099), distant metastasis-free survival (71.9% vs. 81.9%, p = 0.057), or overall survival (84.1% vs. 91.5, p = 0.061) rates. In multivariate analyses, conducting IBR was not associated with increased risks for locoregional recurrence, any recurrence, distant metastasis, or overall death. Conclusion Our findings suggest that IBR following SSM/NSM elicits comparable long-term oncologic outcomes to those of TM alone in the setting of NACT.

Background: The US Food and Drug Administration (FDA) and European Medicines Agency (EMA) approved empagliflozin for reducing cardiovascular mortality and heart failure (HF) hospitalization in patients with both HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). However, limited data are available on the generalizability of empagliflozin to clinical practice. Therefore, we evaluated real-world eligibility and potential cost-effectiveness based on a nationwide prospective HF registry. Methods: A total of 3,108 HFrEF and 2,070 HFpEF patients from the Korean Acute Heart Failure (KorAHF) registry were analyzed. Eligibility was estimated by inclusion and exclusion criteria of EMPagliflozin outcomE tRial in Patients With chrOnic heaRt Failure With Reduced Ejection Fraction (EMPEROR-Reduced) and EMPagliflozin outcomE tRial in Patients With chrOnic heaRt Failure With Preserved Ejection Fraction (EMPEROR-Preserved) trials and by FDA & EMA label criteria. The cost-utility analysis was done using a Markov model to project the lifetime medical cost and quality-adjusted life year (QALY). Results: Among the KorAHF patients, 91.4% met FDA & EMA label criteria, while 44.7% met the clinical trial criteria. The incremental cost-effectiveness ratio of empagliflozin was calculated at US$6,764 per QALY in the overall population, which is far below a threshold of US$18,182 per QALY. The cost-effectiveness benefit was more evident in patients with HFrEF (US$5,012 per QALY) than HFpEF (US$8,971 per QALY). Conclusion There is a large discrepancy in real-world eligibility for empagliflozin between FDA & EMA labels and clinical trial criteria. Empagliflozin is cost-effective in HF patients regardless of ejection fraction in South Korea health care setting. The efficacy and safety of empagliflozin in real-world HF patients should be further investigated for a broader range of clinical applications.

Background: The benefits of transradial access (TRA) over transfemoral access (TFA) for bifurcation percutaneous coronary intervention (PCI) are uncertain because of the limited availability of device selection. This study aimed to compare the procedural differences and the in-hospital and long-term outcomes of TRA and TFA for bifurcation PCI using secondgeneration drug-eluting stents (DESs). Methods: Based on data from the Coronary Bifurcation Stenting Registry III, a retrospective registry of 2,648 patients undergoing bifurcation PCI with second-generation DES from 21 centers in South Korea, patients were categorized into the TRA group (n = 1,507) or the TFA group (n = 1,141). After propensity score matching (PSM), procedural differences, in-hospital outcomes, and device-oriented composite outcomes (DOCOs; a composite of cardiac death, target vessel-related myocardial infarction, and target lesion revascularization) were compared between the two groups (772 matched patients each group). Results: Despite well-balanced baseline clinical and lesion characteristics after PSM, the use of the two-stent strategy (14.2% vs. 23.7%, P = 0.001) and the incidence of in-hospital adverse outcomes, primarily driven by access site complications (2.2% vs. 4.4%, P = 0.015), were significantly lower in the TRA group than in the TFA group. At the 5-year follow-up, the incidence of DOCOs was similar between the groups (6.3% vs. 7.1%, P = 0.639). Conclusion The findings suggested that TRA may be safer than TFA for bifurcation PCI using second-generation DESs. Despite differences in treatment strategy, TRA was associated with similar long-term clinical outcomes as those of TFA. Therefore, TRA might be the preferred access for bifurcation PCI using second-generation DES.

Background: There is insufficient data on the benefits of empiric antibiotic combinations for hospital-acquired pneumonia (HAP). We aimed to investigate whether empiric antipseudomonal combination therapy with fluoroquinolones decreases mortality in patients with HAP. Methods: This multicenter, retrospective cohort study included adult patients admitted to 16 tertiary and general hospitals in Korea between January 1 and December 31, 2019.Patients with risk factors for combination therapy were divided into anti-pseudomonal non-carbapenem β-lactam monotherapy and fluoroquinolone combination therapy groups.Primary outcome was 30-day mortality. Propensity score matching (PSM) was used to reduce selection bias. Results: In total, 631 patients with HAP were enrolled. Monotherapy was prescribed in 54.7% (n = 345) of the patients, and combination therapy was prescribed in 45.3% (n = 286).There was no significant difference in 30-day mortality between the two groups (16.8% vs.18.2%, P = 0.729) or even after the PSM (17.5% vs. 18.2%, P = 0.913). After the PSM, adjusted hazard ratio for 30-day mortality from the combination therapy was 1.646 (95% confidence interval, 0.782–3.461; P = 0.189) in the Cox proportional hazards model. Moreover, there was no significant difference in the appropriateness of initial empiric antibiotics between the two groups (55.0% vs. 56.8%, P = 0.898). The proportion of multidrug-resistant (MDR) pathogens was high in both groups. Conclusion Empiric anti-pseudomonal fluoroquinolone combination therapy showed no survival benefit compared to β-lactam monotherapy in patients with HAP. Caution is needed regarding the routine combination of fluoroquinolones in the empiric treatment of HAP patients with a high risk of MDR.